Gas-operated cartridge feeding system for tubular magazine firearms

ABSTRACT

A gas-operated cartridge feeding system for tubular magazine firearms which is capable of providing an effective utilization of a space in the magazine and a reliable manner of cartridge feeding operation through use of an annular gas chamber formed on the outer circumference of the tubular magazine and a considerably simplified construction realized in a gas-operated portion.

Elite States atent Tazome Jan. 9, 1973 [54] GAS-OPERATED CARTRIDGE [56] References Cited FEEDING SYSTEM FOR TUBULAR MAGAZINE FIREARMS UNITED STATES PATENTS [75] Inventor: Mam gnome, 53: 2.909,101 10/1959 Hillberg ..s9 191 machi,Japan [73] Assigneez SKB Arms Company Tombe Primary Examiner-Stephen C. Bentley machi Japan AttorneyShles1nger, F1tzs1mmons & Shlesmger [22] Filed: Sept. 8, 1971 57 CT [21] PP N05 178,597 A gas-operated cartridge feeding system for tubular magazine firearms which is capable of providing an cf- 30 Foreign Applicafion i it Data fective utilization of a space in the magazine'and a reliable manner of cartridge feeding operation through Jan. 22, 1971 Japan ..46/l9l2 use of an annular gas chamber fol-med on the outer circumference of the tubular magazine and a con- Siderably simplified Construction realized in a In c 58 Field of Search ..s9/191, 191 A Operated pomon' 2 Claims, 3 Drawing Figures GAS-OPERATED CARTRIDGE FEEDING SYSTEM FOR TUBULAR MAGAZINE FIREARMS The present invention generally relates to tubular magazine firearms, and more particularly to a gasoperated cartridge feeding arrangement for use in automatic tubular magazine firearms.

One of the features of the invention resides in that a high-pressure gas produced as a result of explosion of explosives is utilized for feeding cartridges from a tubular cartridge magazine to a firing chamber by way of a gas chamber formed on the outer circumference of the tubular magazine, whereby an effective utilization of the space in the magazine is rendered for the operation of cartridge feeding.

Another feature of the invention resides in that a reliable manner of cartridge feeding operation and a high durability of the mechanism is ensured in accordance with a considerably simplified construction realized in the portion which is operated by the high-pressure gas.

Therefore, it is the principal object of the present invention to provide a new and improved cartridge feeding mechanism for the firearms having tubular cartridge magazines which can assure an effective utilization of a space in the magazine.

It is another object of the present invention to provide a cartridge feeding mechanism of the type described which can ensure a reliable manner of cartridge feeding operation and a high durability with a simple structure.

Essentially, according to the invention, there is provided a gas-operated cartridge feeding system for tubular magazine firearms comprising a barrel; a tubular magazine; a barrel ring coupling said barrel to said magazine; a cylindrical member integrally formed rearward of said barrel ring; a groove axially extending over inner peripheries of said cylindrical member and said barrel ring, said groove being communicated with said barrel through a gas port; a sleeve piston slidably fitted over said tubular magazine, forward portion of said piston being fitted airtightly over said cylindrical member; a gas chamber formed on a periphery of said tubular magazine and defined by said sleeve piston and cylindrical member; and an action bar having one end thereof connected with said sleeve piston thereby to reciprocate therewith; thus automatically feeding the firearms with a cartridge for the following firing.

The above and other objects and features of the invention will be more fully understood from the ensuing description of the accompanying drawings, the later serving for explanatory purposes only and are not intended to in any extent limit this invention and in which drawings:

HO. 1 is a fragmental side view partly shown in vertical section of a tubular magazine firearm including the gas-operated cartridge feeding mechanism according to this invention;

FIG. 2 is a fragmental side sectional view of a principal portion incorporated in the mechanism shown by PK]. 1; and

FIG. 3 schematically illustrates an operational movement of a combination of locking block means shown in FIG. 1.

Referring more particularly to FIG. 1 and 2, a barrel 1 is coupled to a tubular magazine 2 in parallel with each other by means of a barrel ring, generally indicated by reference numeral 4, and attached therewith to a receiver 3. ln said barrel ring 4 is formed a gas port 5 which is communicated at one end thereof with the interior of the barrel 1 and at the other end with a groove 6 axially extending over the inner periphery of the barrel ring 4. Said groove 6 is further extending through a cylindrical member 7 which is integrally formed rearward of the barrel ring 4 and opened in the back of said cylindrical member 7. The cylindrical member 7 has an annular groove 8 formed in the outer periphery thereof in which are fitted a pair of split rings 9 and 10 which are made ofa hard synthetic resin such as polytetrafluoroethylene and steel, respectively. Furthermore, the split ring 9 is affixed with a portion having a smaller diameter 9a on one side thereof. The split ring 9 and 10 are installed in the annular groove 8 by way of initially disposing the split ring 9 in the groove 8 and thereafter fitting the split ring 10 to the smaller diametered portion 9a of the split ring 9, wherein the diameter of the split ring 10 is slightly inferior to that of the split ring 9.

lt should be noted here, in this instance, that the split rings 9 and 10 are given elasticity in increasing and decreasing direction of their diameters, respectively.

A sleeve piston 11 is slidably fitted over the tubular magazine 2, with its forward portion 11a fitted airtightly over the cylindrical member 7. Thus, a gas chamber 12 is formed on the outer periphery of the magazine tube 2 and defined by the sleeve piston 11 and the cylindrical member 7 when the forward portion of the piston 11 is in abutment on the barrel ring 4. Additionally, another annular groove 13 is formed in the inner peripheral wall of the sleeve piston 11 wherein are fitted another pair of split rings 14 made of a hard synthetic resin.

When, in operation, a trigger 18 is pulled under conditions wherein a pressing member 16 of an action spring 15 is in contact with an auto-safety 17 as depicted in FlG. 1, a lever 19 is actuated to pivotally rotate a sear 20 in order to release an engagement thereof with a hammer 21, thereby causing the hammer 21 to strike a firing pin 22 by a spring force so that explosives are exploded to fire a cartridge 23.

A high-pressure gas produced in the barrel by the explosion of the explosives is instantaneously introduced into the gas chamber 12 through the gas port 5 and the groove 6 which are formed in the barrel ring 4 and the cylindrical member 7. The gas introduced into the gas chamber 12 forces the sleeve piston 11 to recede for an instance as far as the forward portion 11a reached the rear end of the cylindrical member 7; whereafter the piston 11 further recedes due to inertia to press the action spring 15 against the spring force thereof through an action bar 24 and a link 25.

The action bar 24 is actuated by the operational movement of the sleeve piston 11 to recede therewith so that a slidable block 26 fitted to the action bar shifts the position of a locking block 27 from the locked to the unlocked as shown in FlGS. 1 and 3, respectively, thereby releasing the lock of the barrel to move a bottom-free member 28 rearwardly.

At the same time, an engagement is released of a shell latch (not shown) which is provided in a carrier latch 29 and adapted to hold a cartridge at an outlet of the tubular magazine against a spring force of a magazine spring 31 pressing the cartridge rearwardly.

Accordingly, the cartridge is pushed out of the magazine 2 by the magazine spring 31 onto the upper portion of a cartridge carrier 30 through a magazine floor 32, in the ordinary manner in the art. The cartridge carrier 30 is coincidently released from an engagement with the carrier latch 29. At this instance, the action bar 24 which has been pushed backwardly by the sleeve piston l l is pushed forwardly by reactionary expansion of the action spring 15 whereby the cartridge carrier 30 is upwardly rotated thereby to forward the cartridge placed thereon to the upper chamber of the barrel. The cartridge is, then, advanced into the firing chamber by the bottom-free member 28 and locked by the locking block 27. Simultaneously with the forward movement of the action bar 24 the sleeve piston 11 is recovered to its original position. Thus, a cartridge feeding operation for the following firing is automatically accomplished.

It will be clear from the foregoing that the cartridge feeding mechanism with a gas chamber in accordance with the present invention provides an effective and maximum utilization of a space defined within the tubular magazine.

It has also another advantage that the high-pressure gas generated in the firing chamber is effected to use by a simple structure of the sleeve piston which is free from troubles and affords a high durability. Furthermore, an automatic cartridge feeding operation is securely performed without a least possibility of malfunction.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to,'falling within the scope of the invention as claimed.

What is claimed is:

l. A gas-operated cartridge feeding system for tubular magazine firearms comprising a barrel; a tubular magazine; a barrel ring coupling said barrel to said magazine; a cylindrical member integrally formed rearward of said barrel ring; a groove axially extending over inner peripheries'of said cylindrical member and said barrel ring, said groove being communicated with said barrel through a gas port; a sleeve piston slidably fitted over said tubular magazine, a forward portion of said piston being fitted airtightly over said cylindrical member; a gas chamber formed on a periphery of said tubular magazine and defined by said sleeve piston and cylindrical member; and an action bar having one end thereof connected with said sleeve piston thereby to reciprocate therewith; thus automatically feeding the firearms with a cartridge for the following firing.

2. A gas-operated cartridge feeding system for tubular magazine firearms as claimed in claim 1, wherein said cylindrical member has an annular groove formed in the outer periphery thereof and a pair of split rings fitted in said groove, one of said rings positioned forward being made of a hard synthetic resin with a smaller diametered portion on its one side and having elasticity in increasing direction of the diameter thereof whereas the other ring positioned rearward is made of steel and has elasticity in decreasing direction of the diameter thereof, thereby ensuring air-tightness of the cylindrical member with said sleeve piston. 

1. A gas-operated cartridge feeding system for tubular magazine firearms comprising a barrel; a tubular magazine; a barrel ring coupling said barrel to said magazine; a cylindrical member integrally formed rearward of said barrel ring; a groove axially extending over inner peripheries of said cylindrical member and said barrel ring, said groove being communicated with said barrel through a gas port; a sleeve piston slidably fitted over said tubular magazine, a forward portion of said piston being fitted airtightly over said cylindrical member; a gas chamber formed on a periphery of said tubular magazine and defined by said sleeve piston and cylindrical member; and an action bar having one end thereof connected with said sleeve piston thereby to reciprocate therewith; thus automatically feeding the firearms with a cartridge for the following firing.
 2. A gas-operated cartridge feeding system for tubular magazine firearms as claimed in claim 1, wherein said cylindrical member has an annular groove formed in the outer periphery thereof and a pair of split rings fitted in said groove, one of said rings positioned forward being made of a hard synthetic resin with a smaller diametered portion on its one side and having elasticity in increasing direction of the diameter thereof whereas the other ring positioned rearward is made of steel and has elasticity in decreasing direction of the diameter thereof, thereby ensuring air-tightness of the cylindrical member with said sleeve piston. 